import java.io.IOException;
import java.net.*;
import java.util.Scanner;

public class UdpEchoClient {
    private DatagramSocket socket = null;
    private  String serverIp = "";
    private  int serverPort = 0;
    public UdpEchoClient(String ip,int port) throws SocketException {
        socket = new DatagramSocket();
        serverIp = ip;
        serverPort = port;
    }
    public  void start() throws IOException {
        System.out.println("客户端启动");
        Scanner scanner = new Scanner(System.in);
        while(true){
            // 从控制台读取数据，作为请求
            System.out.print("-> ");
            String request = scanner.next();
            // 把请求内容构造成 DatagramPacket 对象，发送给服务器。
            DatagramPacket requestPacket = new DatagramPacket(request.getBytes(),request.getBytes().length,
                    InetAddress.getByName(serverIp),serverPort);
            socket.send(requestPacket);
            // 尝试读取服务器返回的响应
            DatagramPacket responsePacket = new DatagramPacket(new byte[4096],4096);
            socket.receive(responsePacket);
            //打印
            String response = new String(responsePacket.getData(), 0, responsePacket.getLength());
            System.out.println(response);

        }
    }

    public static void main(String[] args) throws IOException {
        UdpEchoClient client = new UdpEchoClient("127.0.0.1",9090);
        client.start();

    }

}
